[1][4][5] The Union Medal was instituted by Queen Elizabeth II on 6 April 1952, during the Tercentenary Van Riebeeck Festival.

[8][9][10] The position of the Union Medal in the official order of precedence was revised three times after 1975, to accommodate the inclusion or institution of new decorations and medals, first upon the integration into the South African National Defence Force on 27 April 1994, again when decorations and medals were belatedly instituted in April 1996 for the two former non-statutory forces, the Azanian People's Liberation Army and Umkhonto we Sizwe, and again when a new series of military orders, decorations and medals was instituted in South Africa on 27 April 2003.

The Union Medal is a medallion with a scalloped edge and a raised rim, 38 millimetres in diameter and 3 millimetres thick at the rim and struck in silver, depicting the pre-1994 South African coat of arms encircled with the inscription "UNIE-MEDALJE • UNION MEDAL".

[1][12] The reverse depicts Queen Elizabeth II's royal cipher, a crown over "E II R", and has a raised rim and decorated ribbon suspender, similar to those of the obverse.

[1][12] The clasp, awarded after thirty years of service, was struck in silver and is 1+1⁄4 inches (32 millimetres) wide, with the coat of arms of South Africa in the centre and with a hole at each corner to enable it to be sewn to the ribbon.